This study will examine the mechanism of protein transport through the connecting cilium of mature and differentiating retinal photoreceptors, using light and electron microscopic radioautography. Methods will be developed to block or slow this transport process, by use of microtubule-disrupting drugs and temperature manipulations. This work will develop an experimental technique for subsequent research on photoreceptor outer segment-pigment epithelium interactions in normal and dystrophic retinas. The experimental tissues will also be utilized for continuation of studies on ortho and retrograde axonal transport in retinal ganglion cells, using electron microscopy and biochemical methods. Elucidation of the mechanisms of these transport processes will yield a better understanding of the reciprocal trophic influences of retinal ganglion cells and neurons of visual centers in the brain in normal, diseased and deprived states. BIBLIOGRAPHIC REFERENCES: Bunt, A.H. et al. 1975 Tracing of retinal ganglion cell projections in the monkey with horseradish peroxidase. Assoc. Res. Vision. Ophthalmol. Ann. Meeting. Abstracts p. 69. Bunt, A.H., Haschke, R., Calkins, D. and Lund, R.D. 1975 Specificity of retrograde axonal transport of horseradish peroxidase in the visual system. Society for Neuroscience, V Ann. Meeting. Abstract #154.